CN101645804A - Veneer, communication system and method for detecting connection state of communication interface - Google Patents
Veneer, communication system and method for detecting connection state of communication interface Download PDFInfo
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- CN101645804A CN101645804A CN200810147319A CN200810147319A CN101645804A CN 101645804 A CN101645804 A CN 101645804A CN 200810147319 A CN200810147319 A CN 200810147319A CN 200810147319 A CN200810147319 A CN 200810147319A CN 101645804 A CN101645804 A CN 101645804A
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Abstract
本发明实施例公开了一种单板、通信系统和通信接口连接状态检测方法，为解决现有技术中单板的RS232接口连接状态无法检测的问题而设计。所述单板，包括通信接口和检测电路，其中，所述通信接口包括数据发送信号端、数据接收信号端和信号地端，分别用于与计算机的RS232接口的数据接收信号端、数据发送信号端和信号地端连接；所述通信接口还包括检测端，用于与计算机的RS232接口的请求发送信号端或数据终端准备好信号端连接，并且所述检测端与所述检测电路连接；所述检测电路用于检测所述检测端的信号状态，确定所述单板的通信接口是否与所述计算机的RS232接口电连接。
The embodiment of the invention discloses a single board, a communication system and a method for detecting the connection state of the communication interface, which is designed to solve the problem that the connection state of the RS232 interface of the single board cannot be detected in the prior art. The single board includes a communication interface and a detection circuit, wherein the communication interface includes a data sending signal end, a data receiving signal end and a signal ground end, which are respectively used for the data receiving signal end and the data sending signal end of the RS232 interface of the computer. The terminal is connected to the signal ground terminal; the communication interface also includes a detection terminal, which is used to connect with the RS232 interface request sending signal terminal of the computer or the data terminal ready signal terminal, and the detection terminal is connected to the detection circuit; The detection circuit is used to detect the signal state of the detection terminal, and determine whether the communication interface of the single board is electrically connected with the RS232 interface of the computer.
Description
Technical field
The present invention relates to the communication technology, particularly a kind of veneer, communication system and method for detecting connection state of communication interface.
Background technology
RS232 (Recommended Standard 232, proposed standard 232) is (the Electronic Industries Association of EIA, EIA) a kind of standard for serial communication of releasing in 1962, it has comprised contents such as electrical characteristic, data format, connector specification, simply be described below: adopt non-equilibrium transmission means, there is the speed of a plurality of standards to select, for example 9600,19200,38400,115200 etc., maximum transmission distance is 15 meters; Adopt character-oriented asynchronous communication means, each Frame comprises start bit, data bit, optionally parity check bit, position of rest are formed; Adopt the negative logic mode, promptly the level of logical zero be 5V to 15V, the level of logical one be-5V arrives-15V; Adopt DB25 and two kinds of connectors of DB9, the latter's volume is less, and that uses at present is very general; The DB9 connector has 9 signal pin, and their definition and direction are described as follows:
The TXD data send signal, output
The RXD data reception signal, input
The RTS request to send signal, output
CTS clear to send signal, input
DTR DTR signal, output
The DSR DSR, input
The DCD data carrier detected, input
RI ring index signal, input
The GND signal ground
Though the performance of RS232 serial ports is not high, but because realization simply (needs complicated protocol stack and driver) unlike network interface, cost is low, still obtained using widely, 1 to 2 RS232 serial ports for example generally all is provided on the personal computer, adopt the DB9 connector, can carry out telecommunication by external MODEM (ModulationDemodulation, modulator-demodulator).As long as used processor on the veneer of communication equipment, majority also can provide a RS232 serial ports to be used for debugging, and connector is DB9 or RJ45 normally.
Realize short-range interconnection by a RS232 serial port cable between computer and the veneer, the former moves terminal software (for example Windows operating system carry hyper terminal HyperTerminal software), can show and write down the information that veneer prints, perhaps the user can finish the operation of appointment from computer to the veneer transmitting order to lower levels.This debug serial port on the veneer almost is indispensable in the development phase, because can print various Debugging message or locating information by the debug serial port board software, helps the improvement of positioning problems and board software by collecting these information.
In the use of debug serial port, have such demand: under unattended situation, if the debug serial port cable on the veneer is not plugged, perhaps taken place loosening, board software just there is no need to continue toward debug serial port output information, preferably can be redirected to network interface or internal memory, avoid losing of Debugging message.Realize this function, board software must be able to be known the presence of RS232 serial ports, and adjusts the outlet of type information according to the variation of presence.
In realizing process of the present invention, the inventor finds that there are the following problems at least in the prior art: whether the debug serial port that can not detect veneer is electrically connected with computer by serial, can only guarantee and confirm whether serial interface cable links to each other that the keyboard of for example have or not type information by observing serial ports, pressing computer is observed and had or not echo to judge whether to connect normal by operating personnel.
Summary of the invention
On the one hand, the embodiment of the invention provides a kind of veneer, and whether the communication interface that it can detect veneer is electrically connected with the RS232 interface of computer.
On the other hand, the embodiment of the invention provides a kind of communication system, and whether the communication interface that it can detect veneer is electrically connected with the RS232 interface of computer.
On the one hand, the embodiment of the invention provides a kind of method for detecting connection state of communication interface again, and whether the communication interface that it can detect veneer is electrically connected with the RS232 interface of computer.
A kind of veneer comprises communication interface and testing circuit, wherein,
Described communication interface comprises that data send signal end, data reception signal end and signal ground end, is respectively applied for to send signal end with data reception signal end, the data of the RS232 interface of computer and be connected with the signal ground end;
Described communication interface also comprises the test side, be used for being connected with the request to send signal end or the DTR signal end of the RS232 interface of computer, and described test side is connected with described testing circuit;
Described testing circuit is used to detect the signal condition of described test side, determines whether the communication interface of described veneer is electrically connected with the RS232 interface of described computer.
A kind of communication system comprises veneer, and described veneer comprises communication interface and testing circuit, wherein,
Described communication interface comprises that data send signal end, data reception signal end and signal ground end, is respectively applied for to send signal end with data reception signal end, the data of the RS232 interface of computer and be connected with the signal ground end;
Described communication interface also comprises the test side, be used for being connected with the request to send signal end or the DTR signal end of the RS232 interface of computer, and described test side is connected with described testing circuit;
Described testing circuit is used to detect the signal condition of described test side, determines whether the communication interface of described veneer is electrically connected with the RS232 interface of described computer.
A kind of method for detecting connection state of communication interface comprises:
The data of the communication interface of veneer send signal end, data reception signal end and signal ground end and send signal end with data reception signal end, the data of the RS232 interface of computer respectively and be connected with the signal ground end;
The test side of described communication interface is connected with the request to send signal end or the DTR signal end of the RS232 interface of described computer;
Detect the signal condition of described test side,, determine whether the communication interface of described veneer is electrically connected with the RS232 interface of described computer according to described signal condition.
As from the foregoing, embodiments of the invention are by the request to send signal end of the RS232 interface of detection computations machine or the signal condition of DTR signal end, according to this signal condition, determine whether the communication interface of veneer is electrically connected with the RS232 interface of computer.
Description of drawings
Fig. 1 is a connection diagram of using the testing circuit of triode composition in the embodiment of the invention;
Fig. 2 is a connection diagram of using the testing circuit of photoelectrical coupler composition in the embodiment of the invention;
Fig. 3 is an embodiment of the invention integrated circuit connection diagram;
Fig. 4 is the connection diagram of condition indication circuit in the embodiment of the invention;
Fig. 5 is the communication system connection diagram of the embodiment of the invention;
Fig. 6 is the schematic flow sheet of method in the embodiment of the invention.
Embodiment
Below in conjunction with accompanying drawing embodiments of the invention veneer, communication system and method for detecting connection state of communication interface are described in detail.
Among the embodiment of veneer of the present invention, veneer comprises communication interface and testing circuit, wherein,
Described communication interface comprises that data send signal end, data reception signal end and signal ground end, is respectively applied for to send signal end with data reception signal end, the data of the RS232 interface of computer and be connected with the signal ground end;
Described communication interface also comprises the test side, be used for being connected with the request to send signal end or the DTR signal end of the RS232 interface of computer, and described test side is connected with described testing circuit;
Described testing circuit is used to detect the signal condition of described test side, determines whether the communication interface of described veneer is electrically connected with the RS232 interface of described computer.
The veneer that the embodiment of the invention provides, detect by the request to send signal end or the DTR signal end of testing circuit the RS232 interface of computer, because under no Flow Control communication mode, two signal ends of this of computer are fixed level, so, just can determine whether the communication interface of veneer is electrically connected with the RS232 interface of computer according to testing result.
Following mask body is introduced the principle of the embodiment of the invention:
As everyone knows, the Ethernet interface of veneer can provide the indication of LINK (connection) state, and this function is realized by physical chip.When the both sides of network service linked to each other by netting twine, no matter whether each other in transceive data, they all can regularly send the connection pulse to the other side, and physical chip just can confirm by detecting this pulse whether ethernet link is in connection status.This function of network interface is ethernet standard definition, and the RS232 serial ports does not have this function, and when not having data transmit-receive on the circuit, TXD, RXD holding wire all are fixed levels, promptly be in-5V is to certain level between-15V; When data transmit-receive is arranged, then can produce a burst that comprises start bit, data bit, position of rest, the RS232 serial ports just can't use the connection status detection mode that is similar to network interface like this.
Debug serial port for veneer, the DB9 connector only need use TXD, RXD, three signal pins of GND, other six pins all do not have to use, they mainly are some handshake and status signal, when computer and MODEM (Modulation Demodulation, modulator-demodulator) or other apparatus interconnections, be used as flow control.Can select software flow control, hardware flow control when specifically, computer and peripheral hardware carry out serial communication or not have three kinds of modes of Flow Control.Software flow control is the purpose that is realized Flow Control by the spcial character that the recipient sends Xon, Xoff and so on.Hardware flow control is realized by hardware signals such as RTS, CTS, DTR, DSR, detailed process is: when computer has data to send, must send out a RTS signalisation the other side earlier, cts signal conduct of the other side's loopback is afterwards all set replied, so computer can send data; In case CTS becomes invalid, computer just must suspend transmission, could continue to send data after it returns to effective status.DTR, DSR only are used to show that computer and peripheral hardware are ready to, and not showing can transceive data, and it is to realize by shaking hands of RTS, cts signal that data can be received and dispatched.
The debug serial port of veneer generally uses no Flow Control mode, and this moment veneer and only being connected of computer are: the TXD of the communication interface of veneer, RXD, GND are connected with RXD, TXD, the GND of the RS232 serial ports of computer respectively.No Flow Control mode is easy to realize, the disposal ability of communicating pair enough height or to the not high situation of reliability requirement under use very generally.Under this communication mode, the output signal RTS of serial ports of computers and DTR remain the initial condition behind the electrifying startup, be they be-5V is to a fixed level the between-15V, modally be-9V, and be not subjected to the influence of serial ports transceive data, just can be used as the detection foundation whether Serial Port Line links to each other on the veneer if they are linked into.When Serial Port Line was disjunct, testing circuit was unsettled with the input that the RTS or the DTR of serial ports of computers are connected; When Serial Port Line linked to each other, RTS or DTR that testing circuit can detect serial ports of computers smoothly were fixed level.According to this species diversity, the level that testing circuit output is different, thus just can determine whether Serial Port Line links to each other.Need to prove that by the principle of the invention described above embodiment as can be known, the communication interface of veneer both can be the RS232 interface, also can be the interface of other types, did not all influence the realization of the technical program.When communication interface was the RS232 interface, for the convenience that circuit connects, the test side was preferably clear to send signal end CTS or DSR end DSR.
The technical scheme of the embodiment of the invention promptly is at the veneer and the computer that adopt no Flow Control mode to communicate by letter.For the DB9 connector on the computer, RTS is the 7th pin, DTR is the 4th pin, in can be with them when making serial interface cable one is connected on the DB9 or RJ45 connector of veneer one side debug serial port, other signals for example DSR, CTS, DCD, RI can unsettledly not connect, and whether use a simple testing circuit just can detect serial interface cable then on veneer online.
Circuit on the veneer generally adopts TTL (Transistor Transistor Logic, transistor-transistor logic) level signal form, and the Transistor-Transistor Logic level signal is different with the RS232 level signal, its input high level 〉=2.0V, input low level≤0.8V.Therefore, for the ease of testing circuit serial ports presence signal is outputed to processor or miscellaneous equipment on the veneer, testing circuit is provided with the presence output, and testing circuit also has the function of level signal conversion.
In the present embodiment, testing circuit can adopt circuit form as shown in Figure 1, and wherein, triode is the positive-negative-positive triode, the base stage of this triode is connected with the test side of the communication interface of veneer, and this test side is used for being connected with the RTS or the DTR of computer RS232 serial ports; The grounded collector of triode, emitter are connected with power supply VCC behind resistance, and this power supply adopts the power supply on the veneer, is generally 3.3V or 5V; The emitter of triode also is connected with the presence output of this testing circuit.As shown in Figure 1, because the existence of triode, the presence output is output as the Transistor-Transistor Logic level signal.When serial interface cable was not online, the presence output of this testing circuit was a logic high; When serial interface cable was online, the presence output was a logic low.By reading in the signal condition of line states output, can learn whether the communication interface of veneer is electrically connected with the RS232 serial ports of computer.
Testing circuit can also adopt another kind of implementation, as shown in Figure 2, this testing circuit adopts photoelectrical coupler, this photoelectrical coupler comprises light-emitting diode and phototriode, wherein, the plus earth of described light-emitting diode, negative pole is connected with the test side of the communication interface of veneer, and this test side is used for being connected with the RTS or the DTR of computer RS232 serial ports; The grounded emitter of phototriode, collector electrode are connected with power supply behind resistance; The collector electrode of phototriode also is connected with described presence output.When serial interface cable is online, lumination of light emitting diode, the phototriode conducting, the presence output of this testing circuit is a logic low; When serial interface cable was not online, phototriode turn-offed, and the presence output is a logic high.
In addition, in order to make the board software can be according to the presence of serial ports, switch the outlet of type information flexibly, the presence output of testing circuit 301 is connected with processor 303 on the veneer, as shown in Figure 3, processor 303 regularly reads in the signal condition of line states output, thereby in time learns plugging or taking out of serial interface cable, and handles accordingly.And, in order to save the resource of processor 303, can be connected an edge sense circuit 302 between the processor 303 on presence output and the veneer, be used for when the signal condition of presence output changes, produce interrupt signal and send to processor 303, make processor 303 can in time learn the online situation of serial interface cable.Edge sense circuit 302 is a techniques well known, is not described at this.
In the veneer circuit shown in Figure 3, the presence output of testing circuit 301 also is connected with condition indication circuit 304, is used for the signal condition according to the presence output, produces the indication of corresponding light or sound.Condition indication circuit 304 be embodied as this area common technology, only provide a kind of comparatively simple implementation herein and illustrated.As shown in Figure 4, this condition indication circuit is indicated with light, and it comprises a light-emitting diode, and the negative pole of this light-emitting diode is connected with the presence output behind resistance, and positive pole is connected with power supply.When serial ports is in line states or not during presence, light-emitting diode can be lighted or be extinguished accordingly, when being difficult to observe computer one side whether to have plugged serial interface cable (for example the computer distance is far away), indicate very practical with light or sound.
Corresponding with the embodiment of above-mentioned veneer, the embodiment of the invention also provides a kind of communication system, and as shown in Figure 5, it comprises veneer 501, and described veneer 501 comprises communication interface 503 and testing circuit 505, wherein,
Described communication interface 503 comprises that data send signal end TXD, data reception signal end RXD and signal ground end GND, is respectively applied for to send signal end TXD with data reception signal end RXD, the data of the RS232 interface 504 of computer 502 and be connected with signal ground end GND;
Described communication interface 503 also comprises the test side, be used for being connected with the request to send signal end RTS or the DTR signal end DTR of the RS232 interface 504 of computer 502, and described test side is connected with described testing circuit 505;
Described testing circuit 505 is used to detect the signal condition of described test side, determines whether the communication interface 503 of described veneer 501 is electrically connected with the RS232 interface 504 of described computer 502.
Embodiment of the invention communication system, the request to send signal end or the DTR signal end of the RS232 serial ports 504 by 505 pairs of computers 502 of testing circuit detect, because under no Flow Control communication mode, two signal ends of this of computer are fixed level, so, just can determine whether the communication interface 503 of veneer 501 is electrically connected with the RS232 serial ports 504 of computer 502 according to testing result.This communication system further comprises computer 503, and the RS232 interface 504 of described computer 502 is connected with described veneer 501.The communication system of present embodiment only is to adopt no Flow Control mode to be connected in the veneer of the foregoing description and computer, and all the other technical characterictics are all identical, repeat no more herein.
Corresponding with the foregoing description, the embodiment of the invention also provides a kind of method for detecting connection state of communication interface, as shown in Figure 6, comprising:
Step 601: the data of the communication interface of veneer are sent signal end, data reception signal end and signal ground end send signal end with data reception signal end, the data of the RS232 interface of computer respectively and be connected with the signal ground end;
Step 602: the test side of described communication interface is connected with the request to send signal end or the DTR signal end of the RS232 interface of described computer;
Step 603: detect the signal condition of described test side,, determine whether the communication interface of described veneer is electrically connected with the RS232 interface of described computer according to described signal condition.
The method of the embodiment of the invention, request to send signal end or DTR signal end to the RS232 serial ports of computer detect, because under no Flow Control communication mode, two signal ends of this of computer are fixed level, so, just can determine whether the communication interface of veneer is electrically connected with the RS232 serial ports of computer according to testing result.
In order to make board software switch the outlet of type information flexibly according to the presence of serial ports, described method also comprises: the processor on the veneer regularly reads the signal condition of the test side of described communication interface; Perhaps utilize edge sense circuit, when described signal condition changed, the generation interrupt signal sent to the processor on the veneer.In addition, in order to provide certain indication according to the serial ports presence, described method can also comprise: according to described signal condition, provide the indication of corresponding light or sound.
The above; only be the specific embodiment of the present invention, but protection scope of the present invention is not limited thereto, anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; can expect easily changing or replacing, all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of described claim.
Claims (13)
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102291263A (en) * | 2011-09-02 | 2011-12-21 | 中兴通讯股份有限公司 | State indicating device and equipment, equipment state indicating system and information transmission method |
| CN103514077A (en) * | 2012-06-21 | 2014-01-15 | 深圳市祈飞科技有限公司 | Computer system breaking down warning device and method |
| CN110943888A (en) * | 2019-12-02 | 2020-03-31 | 山东超越数控电子股份有限公司 | Convenient full-function serial port detection method and device |
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2008
- 2008-08-07 CN CN200810147319A patent/CN101645804A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102291263A (en) * | 2011-09-02 | 2011-12-21 | 中兴通讯股份有限公司 | State indicating device and equipment, equipment state indicating system and information transmission method |
| CN103514077A (en) * | 2012-06-21 | 2014-01-15 | 深圳市祈飞科技有限公司 | Computer system breaking down warning device and method |
| CN103514077B (en) * | 2012-06-21 | 2017-08-25 | 深圳市祈飞科技有限公司 | Computer system paralysis warning device and alarm method |
| CN110943888A (en) * | 2019-12-02 | 2020-03-31 | 山东超越数控电子股份有限公司 | Convenient full-function serial port detection method and device |
| CN110943888B (en) * | 2019-12-02 | 2022-09-06 | 超越科技股份有限公司 | Convenient full-function serial port detection method and device |
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Open date: 20100210 |